79 typ4 FI engine - won't hot start?

[gheko76]

van will start every time cold, but as soon as i turn it off it won't restart. any tips for me?

[Wildthings]

New problem or an old problem?

Have you checked that your cold start valve is wired up correctly? If the thermo-time switch is "on" all the time the engine will not start readily when hot. Try removing the plug for the CSV and see if it will hot start for you.

If the TSII sensor is bad the engine may not hot start well. Have you checked the resistance of the TSII sensor through the wiring harness from the plug at the ECU as laid out in the Bentley?

[SGKent]

[gheko76]

Sorry, about the lack of detail. Yes the starter turns but it won't fire.

[gheko76]

Thanks Wildthings! I'll chk that out and let you know if that's it... Thanks!

[Our79Westy]

I have a similar issue and am interested in your ultimate solution.

I try to record on my camera the engine everytime its started. I sit the camera on a trash can and open the engine lid. I always let it warm up for several minutes before driving off (5 to 10 minutes). I then drive 10 minutes at 25mph to the recycling center and shut it off, unload recyclables for 5 minutes and then it will just crank and crank (based on the battery level at the time).

Is that similar to your situation?

I crank for a maximum of 10 seconds, turn off the key, count to 10 mississippi and crank again. Repeat 3 times before waiting longer and try again. Sometimes it starts and sometimes I press the gas pedal lightly and vroom. I know you're not supposed to "gas it" on fuel injection BUT at this specific time the battery was low (as it had been sitting) and I had just picked up Sushi to take home! It was gonna start, or get towed, so I tried it and have had to do this (sporadically) on a few similar occasions since.

I don't recall this happening Before I reconnected the deceleration valve. Reviewing my records it appears my deceleration valve is bad. Explains why the vacuum hose was disconnected and plugged when I took ownership.

Haven't had a chance to disconnect it and replug the vacuum line, but maybe that is a culprit? Vacuum leaks causing too much air entry after the AFM. Someone will know.

I must also say my bus appears to be running rich and may be flooding itself? I hope 2 find the culprit later this summer during engine/transmission refresh.

Good luck on finding the solution and thanks in advance for sharing your diagnosis.
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[busdaddy]

Sounds like both of you need to measure fuel pressure as well as the TS2 OHM readings, far too many possible issues could cause these symptoms, more "ruling out" required.

A ghetto test for "no hot start" is a small squeeze bottle of fuel in the cab with you. When it acts up run around back and pull the Tee out of the S boot and squirt a little fuel in the hole, then put the Tee back and see if it starts or even coughs, if there's no improvement it's likely flooding itself, if it coughs it's not getting enough fuel, now figure out why.
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[gheko76]

so... i replaced ts2 sensor. no improvement. i tested fuel pressure, and all is good. tested the cold start valve by removing it. im still quite sure its flooding itself. any other tips? could it be leaky vacuum lines? it starts fine when cold and idles fine... im definitely exhausting my diagnostic ability...

[Wildthings]

[gheko76]

Ill try unplug ts2 sensor next when hot.

Timing was good.. im told..i had someone else check this who knows more.

Thx Wildthings!

[Wildthings]

[gheko76]

still struggling with this... I had bought a new battery and surprisingly it began to start again when it was hot. But... it only works if it fires back up within the first few seconds... if it misfires its back to turning over and over and over with no firing. It runs like an absolute top when it's running no matter how long and what ever the weather conditions. I also installed a temperature gauge and found that it runs about 200 degrees fahrenheit and will only restart once the temperature has dropped to below 100 degrees fahrenheit. I've pulled the spark plugs and it's not flooded when this happens. Any other thoughts or suggestions?

[busdaddy]

Still waiting for the results of your fuel pressure tests, cold-running-hot-shut off when hot and watched for 1/2 hour?

Also tell us more about your ignition system, points, cap, rotor, wires, plugs and how old your ignition switch is.
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[gheko76]

the fuel pressure I brought to a shop because I don't have the tool or know-how. They reported that everything was good. I could just swap out the fuel pump to test this out.. unless it's the pressure regulator I suppose (?).

I couldn't tell you about the ignition switch, but ignition system uses points - no pertronix or anything like that. I've replaced the wires and plugs (bosch) and I've tested them and they are all sparking. Of course, you'll probably bring up the timing again, and I wouldn't even know how to tell what it's at.

I still have to try your suggestion about squirting gas directly into the s-boot...

[Clatter]

Next time it does it, run back there and unplug the AFM.


Floor it while cranking and cranking - see if it doesn't give a pop and burble then die.
Then plug it back in, and see if it doesn't fire off.

My experience is that they can misjudge how hot they are, and go into cold-start mode, thereby flooding the engine.

Let us know how this does for you....
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What’s That Noise?!?

[Wildthings]

You need to determine if you do or do not have spark at the plugs when it will not start.

[aeromech]

I'm thinking vacuum leak. When it's cold the fifth injector fires and hides the leak. When it's hot the mixture is too lean to fire because of the fifth injector not firing.

I bought a smoke machine on eBay that actually works very well at finding leaks. It was $100 but for me well worth the money.
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